Thermography is a clinical tool for the detection of malignancies, vascular abnormalities and other pathologies by viewing the infrared patterns of living tissue. Work here shows that intraoral thermography is feasible. The radiative power of the thermographic pattern is a function of both tissue emissivity and temperature. Previous work has shown that skin emissivity approaches 1.0, and medical thermographers have ignored emissivity as such. However, a pilot study here has shown that mucosal and tooth emissivities range from 0.73 to 0.94 and that this fact distorts interpretation of the intraoral temperature patterns. If thermography is to become a practical tool for the oral clinician, the variations of intraoral emissivities must be understood so that emissivity adjustments may be preset into thermography systems. In the proposed investigation, the methodology of the pilot study mentioned above will be extended to a large number of subjects. Temperature measurement will be made of intraoral tissues by electronic conduction thermometer and by thermographic scanning. Emissivities varying from unity will cause the thermographic temperature to appear less than the conduction temperature. Emissivities will be computed from this difference.